Mixed cresols, i.e. mixtures containing isomeric methyl-substituted phenols, are obtainable from both natural and synthetic sources. Natural sources include coke, distillates, petroleum, tar sands, and shale oil. Synthetic sources include reactions involving benzene or derivatives thereof. One of the isomers present in mixed cresols, p-cresol, is useful in the preparation of many specialty chemicals. Among them is the antioxidant 2,6-di-tertiary-butyl-p-cresol.
While o-cresol can be effectively removed from mixtures of cresol isomers, via conventional distillation techniques, the boiling points of m- and p-cresols are such that they cannot be easily separated by conventional distillation techniques. Accordingly, there is a need for a process by which m- and p-cresol isomers can be separated without complicated physical and/or chemical manipulation.